html,
body {
  width: 100%;
  position: relative;
}

* {
  margin: 0;
  padding: 0;
}

nav {
  width: 100%;
  height: 80px;
  background-color: white;
  position: fixed;
  left: 0;
  top: 0;
}
nav ul {
  width: 500px;
  display: flex;
  float: right;
  list-style: none;
  justify-content: space-around;
  line-height: 80px;
  margin-right: 100px;
  font-size: 20px;
}
nav a {
  text-decoration: none;
  color: grey;
}
nav img {
  float: left;
  margin: 30px 0 0 100px;
}

section {
  height: 500px;
  width: 100%;
  background-image: url(https://uat-brand.heytap.com/content/dam/heytap-brand/assets/png/daniel-chen-ypZIfpMpyIs-unsplash.jpg);
  background-repeat: no-repeat;
  background-position: 50%;
  background-size: cover;
}

main {
  width: 800px;
  height: 400px;
  margin: auto;
}
main h2 {
  height: 100px;
  background-color: white;
  text-align: center;
  padding-top: 100px;
  font-size: 30px;
}
main h2::after {
  content: "";
  width: 50px;
  height: 8px;
  display: block;
  background-color: #56d085;
  margin-left: 48%;
  margin-top: 10px;
}
main p {
  font-size: 20px;
  text-align: center;
  font-weight: bolder;
  line-height: 30px;
}
main div {
  width: 700px;
  margin: auto;
  color: #666666;
  text-align: center;
  line-height: 30px;
  margin-top: 30px;
  font-weight: bolder;
}

.jiaozhu {
  width: 100%;
  height: 300px;
  background-color: #f8f9fc;
  position: relative;
  box-sizing: border-box;
}
.jiaozhu footer {
  width: 1200px;
  margin: auto;
  padding-top: 50px;
  font-weight: bolder;
}
.jiaozhu footer .left {
  width: 400px;
  height: 200px;
  float: left;
  display: flex;
  flex-direction: column;
  line-height: 40px;
}
.jiaozhu footer .right {
  float: left;
  display: flex;
  flex-direction: column;
  width: 400px;
  height: 200px;
  line-height: 40px;
}
.jiaozhu footer p {
  font-size: 20px;
}
.jiaozhu footer a {
  font-size: 18px;
  text-decoration: none;
  color: gray;
}
.jiaozhu footer a:hover {
  color: #56d085;
}
.jiaozhu footer span {
  color: #cecece;
  position: absolute;
  left: 0;
  bottom: 50px;
}

input {
  width: 50px;
  height: 50px;
  text-align: center;
  line-height: 50px;
  position: fixed;
  right: 30px;
  bottom: 50px;
  display: none;
  cursor: pointer;
  font-size: 20px;
  border: none;
  border-radius: 5px;
  font-weight: bolder;
}
input:hover{
  background-color:rgb(86, 208, 133) ;
  color: white;
}
